Dr. Spector's long-term goal is to conduct sophisticated research on taste and feeding that is explicitly coordinated with anatomical and electrophysiological approaches under a unified experimental framework. The overall goal of the proposed research plan is to specify formal correspondences between the measured psychophysical characteristics of the animal and the electrophysiological properties characterizing peripheral taste afferents. These experiments are designed to make refined psychophysical assessments of taste function before and after selective gustatory nerve transection in rats. The behavioral tasks are designed to measure the detectability, the suprathreshold taste functions, and the between-stimulus discriminability associated with an array of theoretically relevant taste compounds. The specific aims of this research are: 1) to specify the relative contribution of the various gustatory nerves to taste sensibility in an effort to reveal the peripheral organization of the gustatory system; 2) to identify significant features of the neural coding process by comparing psychophysically measured changes in sensory function as a result of specific nerve transection with the known response properties of afferents from both the removed and remaining fields; and 3) to provide a consistent parametric psychophysical data base for rat gustation to guide the analysis and interpretation of neurophysiological findings in both the peripheral and central nervous system. A better understanding of the neural organization of taste processes should facilitate the diagnosis and treatment of chemosensory and neurological disorders.